GM LFX 3.6L V6 Motor Swap

[gtpvette]

Fricking recyclers. Got a call yesterday (5 days after the order) and he told me UPS wont ship the trans in a box as to heavy (I warned him about that). Said he had a lift truck lined up but shipping would go up $200... told him that wont work. OK so he'll deliver to my wife's office as they have a fork lift,, but I now have to provide him enough information to steal my identity as the shipping address is not the same as the billing address. All resolved but what a PITA.


Been looking at radiators and drive shafts in the interim,, probably some of the last major pieces needed. Radiator is fairly easy Mishimoto or Full Blown,,, drive shaft leaves some questions. The idea of a two piece still appeals as I think it'll help dropping the front of the motor down a bit (hood clearance) and I might be able to reuse stock driveshaft. This might also leave more room for the exhaust system. If it'll fit, we'll start with dual exhaust 2.5" (from flange) to small resonated X-pipe then dual 2.25" to the back and some kind of muffler on the ends. Well at least that's the plan.


The back of the LFX is a bit different the LSx. First there is the HP pump mounted on the back of the driver side cylinder head and driven off the camshaft. This leaves a pretty major issue. The motor will need to sit more forward (3.5" or so) in relationship to where the transmission mounts and more importantly where oil pan ends and the transmission begins due to that HP pump. I don't think there is anyway the swaybar will be able to stay even if I cut off part of the pan. I'm real concerned about this as I don't want to be cutting up the firewall.


The other side has the water outlet to the radiator and the two lines that feed the heater core. Not sure how I'll wrap those heater lines back around but not too concerned about these just yet.


Leave for Key West this afternoon for 3 days of fishing. Sweet!
　
　

[Sportsguy83]

Originally Posted by gtpvette

drive shaft leaves some questions. The idea of a two piece still appeals as I think it'll help dropping the front of the motor down a bit (hood clearance) and I might be able to reuse stock driveshaft. This might also leave more room for the exhaust system. If it'll fit, we'll start with dual exhaust 2.5" (from flange) to small resonated X-pipe then dual 2.25" to the back and some kind of muffler on the ends. Well at least that's the plan.


The back of the LFX is a bit different the LSx. First there is the HP pump mounted on the back of the driver side cylinder head and driven off the camshaft. This leaves a pretty major issue. The motor will need to sit more forward (3.5" or so) in relationship to where the transmission mounts and more importantly where oil pan ends and the transmission begins due to that HP pump. I don't think there is anyway the swaybar will be able to stay even if I cut off part of the pan. I'm real concerned about this as I don't want to be cutting up the firewall.

　

You would not be able to use the stock driveshaft as the Camaro DS uses a bolted flange at the transmission and the stock driveshaft uses a slip in yoke into the 86 transmission.

Also, moving the engine/transmission forward might mean you may need to move the radiator forward and modify the radiator support. It may also mean the GTO pan may not fit anymore, or may need completely cutout the transmission cover. I don't know how much smaller is the V6 transmission compared to the T-56/TR-6060, but if its close in size to it, it wouldn't fit over the subframe either. At that point I'd also have concerns on the transmission placement with regards to the shifter.

I think you should attempt in every way possible to measure and see if this engine will actually fit when bolted to the transmission before buying any more parts. Not trying to discourage you, but just looking at the location where the V8s end up, it may require some very involved work to make it fit.

Edit: Reading a bit more on it, saw the transmission is smaller than T-56, which works in your favor.

[gtpvette]

Spent some time with a ruler yesterday measuring, well at least as best as I could. Looks like it’ll fit but nothing is 100% as of yet. The passenger side has a bit of a hole that allows access to the sway bar, steering rack area so I’ve got a pretty good idea regarding distance between the rack and the upper firewall. My best guess is the motor will need go forward to where the trans will be very close to the rack and the sway bar will need to be removed as well as part of the oil pan. There should then be room for the HP pump and water lines on the back of the motor. AC will need a hard 90 on both lines as well as the heater lines. Motor is tall though I suspect hood modification or a new fiberglass hood is in my future.

I’m interested in how you guys are thinking about doing the AC lines that attach to the firewall.

The transmission should be here this week so we’re getting close to pulling the motor. Won’t be putting it up for sale until after I’m sure the new one will fit.

[Sportsguy83]

Originally Posted by gtpvette

I’m interested in how you guys are thinking about doing the AC lines that attach to the firewall.

Custom AC and heater lines once the motor is in and the routing is fully known.

[gtpvette]

Originally Posted by Sportsguy83

Custom AC and heater lines once the motor is in and the routing is fully known.

I'm wondering about the fittings that go into the firewall. Do you know if these are specific to the FRS or are they more generic where that fititng would be available with a hard 90 bend?? If not I'm suspecting they'd need to be cut and welded to a new line.

[Sportsguy83]

Originally Posted by gtpvette

I'm wondering about the fittings that go into the firewall. Do you know if these are specific to the FRS or are they more generic where that fititng would be available with a hard 90 bend?? If not I'm suspecting they'd need to be cut and welded to a new line.

I honestly don't know...

[gtpvette]

While I wait for my trans,, I continue to research things. Let’s continue to talk AC and let me preface it with I’m hardly an expert. I do know I have to have it though.
If I understand AC systems correctly, the compressor compress the refrigerant converting it to high pressure which then flows to the condenser (radiator) to cool it (still high pressure) then off to the evaporator (converts to low pressure to create the cooling) to cool the cabin air. In looking at the AC lines going into the cabin, there is a very small metal line which I assume is the high pressure line going in and the larger is the low pressure coming out. They both stick out way too far and need to be modified to lay closer to the firewall.
The ends of these lines going into the firewall look a bit unique to me. I’ve captured these images from ebay. It looks to me the output side (low pressure) has the bracket attached to it that mounts both to the firewall. The high pressure side just slips into the bracket and is compressed against the firewall. Note the single o-ring.


Does anyone know if these are standard fittings or unique to the FRS???

[Guff]

Very interesting swap! Sub'd for sure!

Here's your Original Post, if you're interested:

I curious is anyone’s taken a look the GM Aluminum v6 LFX or derivative as a swap candidate?? HP is 325-335 TQ curve is nice and flat around 220 ish. Motor light (number I’ve seen is 345 but don’t know if it’s dressed at that weight), twin overhead cam with exhaust manifolds integrated into head. This last item is actually pretty slick. Normal exhaust would just be a down tube then out the back. If I’m not mistaken on the LF3 and LF4 (both 425+ HP) version they bolt the turbos directly to the head.


Low mile LFX motors (Less than 10K) look to be around $2K and a 6 speed less than $1K. These are 2012-2015 Camaro setups. It’s drive by wire so the gas pedal is necessary as well. Might be cheaper to buy a whole wrecked car though and there are lots of them around.


Oil pan might be an issue. The Camaro one is more of a rear sump but they are other that are more of a front sump,,, but might still need to be modified. I’ve spent a bit of time looking at the GTO pan straddling the cross member and rack in some of the pictures. As the V6 pan is shorter the trans would need to move forward a bit but it might fit. A custom pan is always an option but the cost would be a killer.
Some of the Miata guys are putting these into their track cars and seem to like the results. I figured if it fits in a Miata should fit in a FRS.

Line up of Motors,, the late model 3.6l LFX are in lots of GM cars
https://en.wikipedia.org/wiki/GM_High_Feature_engine

[gtpvette]

Thank you,,,,, thought that was lost.

[gtpvette]

Got the transmission and associated parts this weekend. Trans looks nice and is quite clean,,, guess it should be with only 2k miles. Clutch assembly has a bunch of surface rust but I think it'll be OK. Got the shifter and required pigtails although one of the electrical connects (sensor?) on the trans is broken.


Spent more time this weekend looking at the engine compartment. The items coming out of the firewall present some problems with getting the motor back far enough and then being able to service things. In looking at the evaporator it would seem rerouting the AC and heater lines behind the fire wall might solve a few issues. One,, gets them out of the way of the motor and two if the AC lines moved to the drivers side and the heater lines moved to the passenger side they'd be closer to where they hook up. Don't know how difficult it would be getting the evaporator out,,, but I suspect a PITA. Changing the lines looks easy enough though.


I'm not sure yet about the clutch master. The Tilton master seems to be the smallest (75 or 76 series) and a remote reservoir might help a bit but it's still 3"+ off the firewall. I need it smaller or recessed some.

[DustinS]

To get the EVAP housing out, You need to remove the dash, the steering column (a nightmare), and the dash bar. Not a fun job haha.

[gtpvette]

Originally Posted by DustinS

To get the EVAP housing out, You need to remove the dash, the steering column (a nightmare), and the dash bar. Not a fun job haha.

Well crap,,, don't like the way that sounds. It's amazing that mush needs to come out. Dont really want to... but may need to.

[gtpvette]

Not too much to report, parts are trickling in. Clutch master, tensioner, water outlet pipe, steel for mounts etc etc. Want to send the oil pan out this week for a hot tank to clean it up.

Also,, the I'm going to try to use the FRS AC compressor. Location on the motor will be a bit tricky as it'll need to be a bit higher that the OEM AC compressor was to use the tensioner as is. With removing the PS pump routing has changed a bit. I did try an alternate tensioner from a CTS,, wont work and is going back.

[gtpvette]

LFX in a Miata,, sounds pretty good.


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